import 'package:flutter/material.dart';
import 'package:english_words/english_words.dart';

void main() => runApp(new MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final wordPair = new WordPair.random();
    return _startNameGenerate();
  }

  Widget _welcomeFlutter(){
    return new MaterialApp(
      title: 'Welcome to Flutter',
      home: new Scaffold(
        body: new Center(
          child:new RandomWords(),
        ),
        appBar: new AppBar(
          title: new Text('Welcome to Flutter'),
        ),
      ),
    );
  }

  Widget _startNameGenerate(){
    return new MaterialApp(
      title: 'Startup Name generate',
      home: new RandomWords(),
      theme: new ThemeData(
        primaryColor: Colors.white,
      ),
    );
  }

}

class RandomWords extends StatefulWidget {
  @override
  createState() => new RandomWordsState();
}

class RandomWordsState extends State<RandomWords>{
  final _suggestions = <WordPair>[];
  final _biggerFont = const TextStyle(fontSize: 18.0);
  final _saved = new Set<WordPair>();

  @override
  Widget build(BuildContext context) {
//    final wordPair = new WordPair.random();
//    return new Text(wordPair.asPascalCase);
      return _scafforld();
  }

  Widget normal(){
    return new Scaffold(
      appBar: new AppBar(title: new Text('Startup Name Generateor')
      ),
      body:_buildSuggestions(),
    );
  }

  Widget _scafforld(){
    return new Scaffold(
      appBar: new AppBar(
        title:new Text('Startup Name Generator'),
        actions: <Widget>[
          new IconButton(icon: new Icon(Icons.list), onPressed: _pushSaved)
        ],
      ),
      body: _buildSuggestions(),
    );
  }

  Widget _buildSuggestions() {
    return new ListView.builder(
        padding: const EdgeInsets.all(16.0),
        itemBuilder: (context, i) {
          // 在每一列之前，添加一个1像素高的分隔线widget
          if (i.isOdd) return new Divider();

          // 语法 "i ~/ 2" 表示i除以2，但返回值是整形（向下取整），比如i为：1, 2, 3, 4, 5
          // 时，结果为0, 1, 1, 2, 2， 这可以计算出ListView中减去分隔线后的实际单词对数量
          final index = i ~/ 2;
          // 如果是建议列表中最后一个单词对
          if (index >= _suggestions.length) {
            // ...接着再生成10个单词对，然后添加到建议列表
            _suggestions.addAll(generateWordPairs().take(10));
          }
          return _buildRow(_suggestions[index]);
        }
    );
  }

  Widget _buildRow(WordPair pair){
    final alreadySaved = _saved.contains(pair);
    return new ListTile(
        title:new Text(
        pair.asPascalCase,
      style:_biggerFont,
      ),
      trailing: new Icon(
        alreadySaved?Icons.favorite:Icons.favorite_border,
        color: alreadySaved?Colors.red:null,
      ),
      onTap: (){
          setState((){});
          if(alreadySaved){
            _saved.remove(pair);
          }
          else{
            _saved.add(pair);
          }
      },
    );
  }

  void _pushSaved() {
    Navigator.of(context).push(
      new MaterialPageRoute(
        builder: (context) {
          final tiles = _saved.map(
                (pair) {
              return new ListTile(
                title: new Text(
                  pair.asPascalCase,
                  style: _biggerFont,
                ),
              );
            },
          );
          final divided = ListTile
              .divideTiles(
            context: context,
            tiles: tiles,
          )
              .toList();

          return new Scaffold(
            appBar: new AppBar(
              title: new Text('Saved Suggestions'),
            ),
            body: new ListView(children: divided),
          );
        },
      ),
    );
  }

}